It has been proposed to control some functionalities of a motor vehicle, such as unlocking the doors of the vehicle, by means of a mobile terminal, for example a cell phone commonly used by the owner of the vehicle.
In order to permit this control only to persons who are indeed authorized, a virtual key is used which is stored in the cell phone, the presence of which is verified by an electronic control unit of the vehicle before commanding the unlocking of the doors.
In the same way that there are several physical keys for each vehicle so that the owner of the vehicle can easily lend or rent out the vehicle thereof to another user, it is necessary to be able to assign several virtual keys to several cell phones.
The method allowing the owner to transmit a virtual key to the cell phone of another user currently consists, for the owner, in sending to a server a virtual key request accompanied by the cell phone number to which this virtual key should be assigned.
Then, the server develops a virtual key and transmits it to the cell phone. For security reasons, this virtual key is provided to be stored in a physical security element of the mobile terminal, for example in a protected area of the SIM (Subscriber Identity Module) card of this cell phone.
In order to access this physical security element, it is necessary beforehand to request special access from the cell phone operator.
This request for access is restrictive for various reasons. Thus, it complicates the process for virtual key sharing. It also slows it down since the speed of the user receiving the virtual key depends on the speed of the operator in responding to the request for access to the physical security element. Finally, setting up this access authorization, in an automatic manner, proves to be complicated in practice.
Moreover, since some operators or manufacturers of cell phones do not wish to give access to the protected area of the cell phones thereof, the loan of the motor vehicle may sometimes prove to be impossible.